The present invention relates to a vehicle seat, particularly to a vehicle seat for suppressing damage of an interior material provided on a seat frame to maintain a favorable seat shape.
When a vehicle such as a motor vehicle is impacted from the front side, the rear side, and the side, due to inertia force, a passenger is moved in the colliding direction of forward, rearward, and sideward, respectively, relative to the vehicle. Since a great shock is given to the passenger at this time, there is a need for ensuring safety of the passenger.
When the vehicle is impacted from the front side, the rear side, and the side, a technique of absorbing a load at the time of impact, that is, impact energy by a buffer structure (such as an engine compartment and a console box) provided on the vehicle body side to ensure the safety of the passenger is used. In order to transmit such impact energy to the vehicle body side to be absorbed, there is a need for improving rigidity of a vehicle seat on which the passenger is seated to efficiently transmit the impact energy to the vehicle body side.
When the vehicle is impacted from the rear side, and when baggage or the like is placed on the rear side of the passenger, the baggage is rapidly moved forward due to the inertia force. Thus, there is a need for protecting the passenger from a colliding object such as the baggage. Further, when the vehicle is impacted from the rear side, the passenger's body is moved rearward. Thus, there is a need for reliably holding the passenger's body by the vehicle seat. Therefore, in order to protect the passenger from the colliding object, there is also a need for improving the rigidity of the vehicle seat.
In the vehicle seat, there is a need for providing the rigidity in order to hold a seating space of the passenger, and to ensure the safety of the passenger without deformation not only due to the shock in the front and rear direction but also shock energy when the vehicle is impacted on a side surface.
Japanese Patent Application Publication No. 2008-514490 (“the '490 Publication”) relates to a seat back structure for a vehicle seat and discloses a vehicle seat in which plate-shaped front and rear shells formed into a seat back shape are arranged to face each other and adhered to each other.
With such a configuration, the rigidity against the shock in the front and rear direction as well as the left and right direction (the seat width direction) can be improved in the seat back of the vehicle seat.
The '490 Publication discloses a configuration that the plate-shaped front and rear shells respectively arranged in the front and rear direction are adhered to each other in a seat back frame.
However, in the technique of this publication, an inner surface portion of the front shell is formed to be smaller than an inner surface portion of the rear shell, and the front and rear shells are overlapped with and jointed to each other on a surface on the side where the passenger is seated.
Therefore, with the vehicle seat disclosed in the '490 Publication, when the passenger is seated, a load of the passenger is applied onto a part where the front and rear shells are overlapped with and jointed to each other (hereinafter, called the “overlapping portion”). The overlapping portion has a level difference due to plate thickness of the front and rear shells. Thus, when the passenger moves on the seat, interior materials such as a cushion material and a skin material arranged between the seat back frame and the passenger are rubbed with the overlapping portion and then worn away. As a result, there is a problem that the interior materials are damaged, and hence strength is lowered.
Also, there is the level difference in the overlapping portion of the front and rear shells on the side where the passenger is seated. Thus, when the cushion material is disposed thereon, the cushion material is deformed, so that there is a disadvantage that an outer appearance of the vehicle seat is deteriorated.
An object various embodiments of the present invention is to provide a vehicle seat for suppressing damage of the interior materials such as the cushion material and the skin material to favorably maintain a seat shape.